Portugal boss Fernando Santos has said that his side will have to be at their best to overcome Switzerland and reach the quarter-finals of the 2022 World Cup.

A Selecao finished top of Group H, picking up six points from their three matches, in order to book their spot in the knockout round of the competition.

Switzerland are their opponents in the round of 16, and Santos has detailed the challenge that will be waiting for his side on Tuesday night.

"This Switzerland team have played together for a long time. Whenever we've played them they've been tough, extremely competitive matches for both sides," Santos told reporters.

"Switzerland are very well-organised, know the game inside out, have high-quality players and know what they're doing on the pitch.

"One need only look at their last game. They were 2-1 down but the Swiss team never lost their shape. They kept playing the same way, with the same calmness, focus and objectives. That's the Switzerland I expect.

"They are not a defensive team at all. They did not play defensively against Brazil. [Xherdan] Shaqiri didn't play because he was injured, the goalkeeper and centre-back didn't play because they were ill, but they kept the same formation.

"In relation to the last matches we played against them, they have a small nuance. They usually play two in midfield, but the rest is similar.

"The wide players are inverted, so they can cut inside, looking for space between the lines. Before they played a 1-2 and know they play more of a 2-1, with [Djibril] Sow pushed further forward.

"We've analysed this, but it doesn't change their pattern of play. They play out from the back and [Yann] Sommer is good with his feet. It won't be a very vertical game like against Korea."

Santos was also asked about Rafael Leao during his press conference, as there have been calls for the AC Milan attacker to be introduced into the starting XI.

The Portugal head coach has said that the 23-year-old "has enormous potential" but is yet to fully understand the role that he needs to play in his side.

"He has enormous potential. He will have a great career but he is experiencing the normal difficulties of a player who enjoys a certain freedom in his club team and is not called upon to balance the game," said Santos.

"He has made a fantastic effort, but there are players who stand out in some teams and not in others. This does not detract from the qualities of him and the trust I have in him."

Leao has only played 59 minutes of football at the 2022 World Cup, but he found the back of the net against Ghana in the team's competition opener.